diff options
Diffstat (limited to 'nbd/client.c')
| -rw-r--r-- | nbd/client.c | 195 |
1 files changed, 192 insertions, 3 deletions
diff --git a/nbd/client.c b/nbd/client.c index 88f2ada..be5f08d 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -71,6 +71,177 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); */ + +static int nbd_handle_reply_err(uint32_t opt, uint32_t type, Error **errp) +{ + if (!(type & (1 << 31))) { + return 0; + } + + switch (type) { + case NBD_REP_ERR_UNSUP: + error_setg(errp, "Unsupported option type %x", opt); + break; + + case NBD_REP_ERR_INVALID: + error_setg(errp, "Invalid data length for option %x", opt); + break; + + default: + error_setg(errp, "Unknown error code when asking for option %x", opt); + break; + } + + return -1; +} + +static int nbd_receive_list(QIOChannel *ioc, char **name, Error **errp) +{ + uint64_t magic; + uint32_t opt; + uint32_t type; + uint32_t len; + uint32_t namelen; + + *name = NULL; + if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { + error_setg(errp, "failed to read list option magic"); + return -1; + } + magic = be64_to_cpu(magic); + if (magic != NBD_REP_MAGIC) { + error_setg(errp, "Unexpected option list magic"); + return -1; + } + if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) { + error_setg(errp, "failed to read list option"); + return -1; + } + opt = be32_to_cpu(opt); + if (opt != NBD_OPT_LIST) { + error_setg(errp, "Unexpected option type %x expected %x", + opt, NBD_OPT_LIST); + return -1; + } + + if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) { + error_setg(errp, "failed to read list option type"); + return -1; + } + type = be32_to_cpu(type); + if (type == NBD_REP_ERR_UNSUP) { + return 0; + } + if (nbd_handle_reply_err(opt, type, errp) < 0) { + return -1; + } + + if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) { + error_setg(errp, "failed to read option length"); + return -1; + } + len = be32_to_cpu(len); + + if (type == NBD_REP_ACK) { + if (len != 0) { + error_setg(errp, "length too long for option end"); + return -1; + } + } else if (type == NBD_REP_SERVER) { + if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) { + error_setg(errp, "failed to read option name length"); + return -1; + } + namelen = be32_to_cpu(namelen); + if (len != (namelen + sizeof(namelen))) { + error_setg(errp, "incorrect option mame length"); + return -1; + } + if (namelen > 255) { + error_setg(errp, "export name length too long %d", namelen); + return -1; + } + + *name = g_new0(char, namelen + 1); + if (read_sync(ioc, *name, namelen) != namelen) { + error_setg(errp, "failed to read export name"); + g_free(*name); + *name = NULL; + return -1; + } + (*name)[namelen] = '\0'; + } else { + error_setg(errp, "Unexpected reply type %x expected %x", + type, NBD_REP_SERVER); + return -1; + } + return 1; +} + + +static int nbd_receive_query_exports(QIOChannel *ioc, + const char *wantname, + Error **errp) +{ + uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC); + uint32_t opt = cpu_to_be32(NBD_OPT_LIST); + uint32_t length = 0; + bool foundExport = false; + + TRACE("Querying export list"); + if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { + error_setg(errp, "Failed to send list option magic"); + return -1; + } + + if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) { + error_setg(errp, "Failed to send list option number"); + return -1; + } + + if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) { + error_setg(errp, "Failed to send list option length"); + return -1; + } + + TRACE("Reading available export names"); + while (1) { + char *name = NULL; + int ret = nbd_receive_list(ioc, &name, errp); + + if (ret < 0) { + g_free(name); + name = NULL; + return -1; + } + if (ret == 0) { + /* Server doesn't support export listing, so + * we will just assume an export with our + * wanted name exists */ + foundExport = true; + break; + } + if (name == NULL) { + TRACE("End of export name list"); + break; + } + if (g_str_equal(name, wantname)) { + foundExport = true; + TRACE("Found desired export name '%s'", name); + } else { + TRACE("Ignored export name '%s'", name); + } + g_free(name); + } + + if (!foundExport) { + error_setg(errp, "No export with name '%s' available", wantname); + return -1; + } + + return 0; +} + int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags, off_t *size, Error **errp) { @@ -121,28 +292,44 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags, uint32_t namesize; uint16_t globalflags; uint16_t exportflags; + bool fixedNewStyle = false; if (read_sync(ioc, &globalflags, sizeof(globalflags)) != sizeof(globalflags)) { error_setg(errp, "Failed to read server flags"); goto fail; } - *flags = be16_to_cpu(globalflags) << 16; + globalflags = be16_to_cpu(globalflags); + *flags = globalflags << 16; + TRACE("Global flags are %x", globalflags); if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { + fixedNewStyle = true; TRACE("Server supports fixed new style"); clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; } /* client requested flags */ + clientflags = cpu_to_be32(clientflags); if (write_sync(ioc, &clientflags, sizeof(clientflags)) != sizeof(clientflags)) { error_setg(errp, "Failed to send clientflags field"); goto fail; } - /* write the export name */ if (!name) { error_setg(errp, "Server requires an export name"); goto fail; } + if (fixedNewStyle) { + /* Check our desired export is present in the + * server export list. Since NBD_OPT_EXPORT_NAME + * cannot return an error message, running this + * query gives us good error reporting if the + * server required TLS + */ + if (nbd_receive_query_exports(ioc, name, errp) < 0) { + goto fail; + } + } + /* write the export name */ magic = cpu_to_be64(magic); if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { error_setg(errp, "Failed to send export name magic"); @@ -176,7 +363,9 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags, error_setg(errp, "Failed to read export flags"); goto fail; } - *flags |= be16_to_cpu(exportflags); + exportflags = be16_to_cpu(exportflags); + *flags |= exportflags; + TRACE("Export flags are %x", exportflags); } else if (magic == NBD_CLIENT_MAGIC) { if (name) { error_setg(errp, "Server does not support export names"); |